This invention relates to a window.
The sash and case vertically sliding window is the most traditional window still in current production and use. It is also the lost difficult to insulate, draught proof and keep silent, but retains aesthetic appeal absent from most modern double glazed windows. Problems have also arisen with escape from the conventional windows because of difficulties in attaining the maximum escape height due to the relatively large size of the lower sash. Attempts have been made to improve the insulation properties of conventional sash and case windows using sliding and/or lift out internal secondary glazing but these have proved unacceptable to end users/building occupiers because of difficulties in access to the sash and case window for basic cleaning purposes.
Other attempts to overcome the problems associated with conventional sash and case windows have been made in the past using casement based outward opening and/or pivoting, arrangements which have lost appeal for the following, reasons:
1. Unacceptable and/or inconsistent forward/outward projection of opening sashes reduces the aesthetic effect, and there is a risk of sash/pedestrian collision at ground floor level.
2. The unacceptable bulky appearance of exposed frame and sash evident on external elevations and the resultant reduction in glass size, enecessitated by the method of opening, both of which are aesthetically displeasing.
3. The difficulty of weather sealing because gasketry (sealing) has to change planes vertically and is therefore not continuous thereby allowing ingress of wind and water.
According to the present invention, there is provided a window comprising a frame and first and second opening sashes, the second sash being openable inwardly of the frame and being glazed substantially over the full height of the window. Preferably, the first sash is slidable in the frame.
In the event of the window being part of a replacement or major repair/renovation process the first sash could be formed by the original upper sash being salvaged or recycled. It can be hung on weighted cords or chains, or on sprung balances. The second (inner) sash may be full size within the frame of the window and can be bottom and/or side hung for inward opening. One mechanism for doing this may be any conventional xe2x80x9ctilt and turnxe2x80x9d opening mechanism. Preferably, a seal is provided around the second sash which meets the frame in a single plane. It can be double glazed its full height with a hermetically sealed unit.
The second sash can have a non-functional xe2x80x9cmeeting tailxe2x80x9d in line with bottom rail of the outer or upper sash (when in its uppermost position). However, the meeting rail may co-operate with a sealing strip provided on the outer sash. The strip may seal against the second sash when the window is fully closed, thereby helping to secure the first sash to prevent noise (eg wind rattle) caused by movement of the first sash. Astragal bars can be incorporated in the outer sash and in the bottom half of the inner sash (ie below the meeting rail) to suit decorative requirements.
The outer sash, being vertically slidable, can be lowered to a desired position for cleaning both faces of the glass from within the building, at a safe working height to suit the individual. This sash can also be positioned such that it forms a safety balustrade while cleaning or servicing the sashes.
The mechanism controlling the movement of the second (inner) sash can be exposed, or semi or totally concealed; locks can be provided to limit its operation to authorised persons and/or to ensure that bottom hung and side hung actions of the hinging system cannot be achieved at the same time. Preferably the second sash can over-rebate the frame on its inward-facing surface. This provides clean uninterrupted cover and conceals operating gear and any adjustment from view.
Both sashes can be glazed with single or double glazed units from within the building and can be easily removed for repairs or replacement; the second sash by a concealed release mechanism at the top; the first (outer) sash by opening the inner sash, removing the parting bead between the two sashes, and releasing the weights or balances. Reinstallation may be by the same process in reverse
The outer (first) sash may improve the decorative appearance of the window, which should look similar to a traditional sash and case window, but retain the advantages of double glazing in terms of its insulation, quick release, opening and easy cleaning. thee outer sash also provides additional thermal and acoustic insulation at the top portion of the window. In effect, in the fully closed position, with the outer sash up, the top part of the window unit may be triple glazed.